The disposal of trash, garbage, sewage treatment sludge, industrial wastes, etc. has long been a problem in this country and likely will not be one which is solved satisfactorily in the very near future. While the incineration of such wastes to generate power continues to be a major approach to disposal, such methods have been on the decline due to the strict enforcement of air pollution laws. Thus, a proliferation of landfill operations, especially in urbanized areas, has been experienced in recent years. However, with increasing suburban population densities and stringent state and federal regulations regarding the ecology, landfill operators have had to endure generally accelerating costs.
A traditional landfill operation involves dumping the wastes into a natural or artificial cavity in the earth, leveling, compacting and/or treating the wastes, spreading a layer of earth or soil over the top surface of the wastes, essentially to prevent the escape of odors and fumes, and then continuing the landfilling with successive layers of refuse and soil until the site is filled. Typical of such operations are those shown in U.S. Pat. Nos. 3,614,867 to Nieman and 3,732,697 to Dickson.
It has been suggested to replace the earthen covering over compacted wastes with a foamed plastic layer to eliminate the expense of transporting fill dirt to the site and operating large earth moving equipment to spread and compact it as well as the consumption of significant volumes of the landfill site with non-waste material (i.e., soil) to the detriment of the operator. One of such advances is described in U.S. Pat. No. 3,466,873 to Present wherein successive layers of refuse are covered with foamed polyurethane-, polyether- or polyester-based plastic resins to provide a rigid cellular structure impervious to gas or water over each layer of refuse. U.S. Pat. Nos. 4,421,788 and 4,519,338 to Kramer et al. also teach sealing a landfill with a hardenable foam cover of a liquid synthetic resin, such as a precondensate of urea and formaldehyde, which hardens and cures very soon after it is deposited.
The need has arisen for an improved and relatively inexpensive, long duration barrier layer for application to a surface, such as a landfill, which insulates the surface from the environment and which can also provide odor control, lack of substantial filling volume, and safety to the ecology.